Compositions and methods for treating kidney disease

ABSTRACT

The present invention relates to methods and compositions for the prevention and treatment of renal damage. The invention provides protein-based renal therapeutic agents for administration to subjects in order to prevent or treat renal degeneration or damage.

This application is a divisional of U.S. patent application Ser. No. 11/613,658, filed Dec. 20, 2006, now U.S. Pat. No. 7,585,501 now allowed, which is a continuation-in-part of U.S. patent application Ser. No. 11/508,701 filed Aug. 23, 2006. U.S. patent application Ser. No. 11/508,701 is a continuation-in-part of U.S. patent application Ser. No. 10/464,368 filed Jun. 16, 2003, now abandoned which claims priority to U.S. Provisional Application No. 60/388,970 filed Jun. 14, 2002. U.S. patent application Ser. No. 11/508,701 also claims priority to U.S. Provisional Application Ser. No. 60/710,803 filed Aug. 23, 2005.

BACKGROUND OF INVENTION

A. Field of the Invention

The present invention relates to compositions and methods for the prevention and treatment of renal damage. In particular, the invention relates to administration of novel therapeutics to subjects in order to prevent or treat renal degeneration or damage. These novel therapeutics include antibodies, peptides, and small molecules based upon the WISE/SOST family of proteins.

B. Background of the Invention

The mammalian renal system serves primary roles both in the removal of catabolic waste products from the bloodstream and in the maintenance of fluid and electrolyte balances in the body. Renal failures are, therefore, life-threatening conditions in which the build-up of catabolites and other toxins, and/or the development of significant imbalances in electrolytes or fluids, may lead to the failure of other major organs systems and death. Chronic renal failure is a debilitating and life-threatening disease for which no adequate treatment exists.

Tubular damage and interstitial fibrosis are the final common pathways leading to end stage renal disease. Irrespective of the nature of the initial renal injury, the degree of tubular damage parallels the impairment of renal function. Once nephronic degeneration or tubular damage is established, it cannot be reversed or repaired by currently available treatment, and renal function deteriorates to renal failure, which is often life threatening. Renal damage and failure can only be managed through dialysis or organ transplantation.

Dialysis dependency is one of the leading causes of morbidity and mortality in the world. Despite advancement in understanding the pathophysiology of renal diseases, the incidence of end-stage renal disease is increasing. Approximately 600 patients per million receive chronic dialysis each year in the United States, at an average cost approaching $60,000-$80,000 per patient per year. Of the new cases of end-stage renal disease each year, approximately 28-33% are due to diabetic nephropathy (or diabetic glomerulopathy or diabetic renal hypertrophy), 24-29% are due to hypertensive nephrosclerosis (or hypertensive glomeruloscierosis), and 15-22% are due to glomerulonephritis. The 5-year survival rate for all chronic dialysis patients is approximately 40%, but for patients over 65, the rate drops to approximately 20%.

A need remains, therefore, for treatments that will prevent the progressive loss of renal function which has caused almost two hundred thousand patients in the United States alone to become dependent upon chronic dialysis, and which results in the premature deaths of tens of thousands each year.

SUMMARY OF INVENTION

The present invention provides protein-based renal therapeutic agents for administration to subjects in, or at risk of, renal failure. The methods and compositions of the present invention may be used to prevent, inhibit, delay, or reverse nephronic degeneration, which otherwise leads to the need for renal replacement therapy to prevent death. Specifically, the present invention is directed to compositions and methods that regulate the interaction between SOST and WISE proteins with their natural receptors. Exemplary natural receptors for WISE and SOST proteins include, but are not limited to, LRP5, LRP6, and BMP molecules. Methods and compositions of the present invention therefore provide a therapy that may reverse nephronic degeneration and/or prevent the progressive loss of renal function, thereby preventing premature death.

Methods of the invention include administering a therapeutically effective amount of an antibody to a patient in which the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of a developmental regulator and the antibody interferes with the interaction between at least two developmental regulators thereby providing nephron protection and/or regeneration. Exemplary developmental regulators include those molecules disclosed as SEQ ID NOS: 1-217.

In some embodiments of the invention, the developmental regulators are a ligand and the ligand's natural receptor. For example, the ligand may be WISE and a known WISE receptor, such as LRP5, LRP6, BMP2, or BMP7. Another exemplary pair is SOST protein and one or more of its known receptors, e.g., LRP5, LRP6, BMP6, or BMP7.

The invention also provides a pharmaceutical composition for administration to a subject that includes an antibody and optional excipient(s). Antibodies suitable for the present invention may be administered in a therapeutically effective amount resulting in an improvement of renal function by at least 10%, 15%, 20%, 25%, or more following renal insult, as measured by a standard assay of renal function. Examples of such assays are provided herein. For example, a suitable assay of renal function include, determining rates of increase in Blood Urea Nitrogen (BUN) levels, rates of increase in serum creatinine, static measurements of BUN, static measurements of serum creatinine, glomerular filtration rates (GFR), ratios of BUN/creatinine, and serum concentrations of sodium (Na+). Suitable excipients include, but are not limited to, saline, buffered saline, dextrose, water, glycerol, ethanol, and combinations thereof.

Antibodies of the invention may be monoclonal, polyclonal, humanized, or a fragment thereof (Fab or Fab₂), as described in greater detail, below. Preferably, antibodies of the present invention specifically bind a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of a developmental regulator and the antibody interferes with the interaction between at least two developmental regulators thereby providing nephron protection and/or regeneration. More preferably, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of or encoded by SEQ ID NOS. 2, 4, 6, 8, 10, 12, 14, 15-18, 20, 85-87, 91, 93, 95, 98, 101, 103, 105, and 109-217; preferably SEQ ID NOS. 90-108, 215, and 216; more preferably, SEQ ID NOS. 19-89, 15-18, and 217; preferentially, SEQ ID NOS. 90-93, 215, and 216; alternatively, SEQ ID NOS. 15-20 and 217; more preferably, SEQ ID NOS. 92, 93, and 215; more preferably SEQ ID NOS. 15-18 and 217; ideally, SEQ ID NOS. 15-18. Alternatively, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of positions 50-62, 68-80, or 83-98 of SEQ ID NOS. 20, and 215-217.

The method and pharmaceutical composition of the invention may be administered to any subject receiving renal injury, chemical or physical insult resulting in apoptosis or necrosis of renal tissue, disease, or those otherwise at risk of chronic renal failure. For example, subjects in, or at risk of, chronic renal failure, or at risk of the need for renal replacement therapy, include but are not limited to the following: subjects which may be regarded as afflicted with chronic renal failure, end-stage renal disease, chronic diabetic nephropathy, hypertensive nephrosclerosis, chronic glomerulonephritis, hereditary nephritis, and/or renal dysplasia; subjects having a biopsy indicating glomerular hypertrophy, tubular hypertrophy, chronic glomerulosclerosis, renal cell carcinoma, and/or chronic tubulointerstitial sclerosis; subjects having an ultrasound, MRI, CAT scan, or other non-invasive examination indicating renal fibrosis.

The methods and compositions of the present invention may be utilized for any mammalian subject. For example, human subjects or patients, domesticated mammals (e.g., dogs, cats, horses), mammals with significant commercial value (e.g., dairy cows, beef cattle, sporting animals), mammals with significant scientific value (e.g., captive or free specimens of endangered species), or mammals which otherwise have value.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. The following references provide one of skill with a general definition of many of the terms used in this invention: Singleton et al., Dictionary of Microbiology and Molecular Biology (2nd Ed. 1994); The Cambridge Dictionary of Science and Technology (Walker ed., 1988); The Glossary of Genetics, 5th Ed., R. Rieger et al. (eds.), Springer Verlag (1991); and Hale & Marham, The Harper Collins Dictionary of Biology (1991). As used herein, the following terms have the meanings ascribed to them unless specified otherwise.

As used herein, “antibody” includes reference to an immunoglobulin molecule immunologically reactive with a particular antigen, and includes both polyclonal and monoclonal antibodies. The term also includes genetically engineered forms such as chimeric antibodies (e.g., humanized murine antibodies) and heteroconjugate antibodies (e.g., bispecific antibodies). The term “antibody” also includes antigen binding forms of antibodies, including fragments with antigen-binding capability (e.g., Fab′, F(ab′)₂, Fab, Fv and rIgG). See also, Pierce Catalog and Handbook, 1994-1995 (Pierce Chemical Co., Rockford, Ill.). See also, e.g., Kuby, J., Immunology, 3^(rd) Ed., W.H. Freeman & Co., New York (1998). The term also refers to recombinant single chain Fv fragments (scFv). The term antibody also includes bivalent or bispecific molecules, diabodies, triabodies, and tetrabodies. Bivalent and bispecific molecules are described in, e.g., Kostelny et al. (1992) J Immunol 148:1547, Pack and Pluckthun (1992) Biochemistry 31:1579, Hollinger et al., 1993, supra, Gruber et al. (1994) J Immunol:5368, Zhu et al. (1997) Protein Sci 6:781, Hu et al. (1996) Cancer Res. 56:3055, Adams et al. (1993) Cancer Res. 53:4026, and McCartney, et al. (1995) Protein Eng. 8:301.

An antibody immunologically reactive with a particular antigen can be generated by recombinant methods such as selection of libraries of recombinant antibodies in phage or similar vectors, see, e.g., Huse et al., Science 246:1275-1281 (1989); Ward et al., Nature 341:544-546 (1989); and Vaughan et al, Nature Biotech. 14:309-314 (1996), or by immunizing an animal with the antigen or with DNA encoding the antigen.

The term “insult” refers to any injury or damage to a cell or population of cells that results in cell death or apoptosis, necrosis, altered kidney function, or decreased kidney function. An insult may have a variety of causes including, but not limited to, disease, chemical injury, or physical injury.

The phrase “specifically binds” when referring to a protein or peptide, refers to a binding reaction that is determinative of the presence of the protein, in a heterogeneous population of proteins and other biologics. Thus, under designated immunoassay conditions, the specified antibodies bind to a particular protein sequence at least two times the background and more typically more than 10 to 100 times background.

Specific recognition by an antibody under such conditions requires an antibody that is selected for its specificity for a particular protein. For example, antibodies raised against a particular protein, polymorphic variants, alleles, orthologs, and conservatively modified variants, or splice variants, or portions thereof, can be selected to obtain only those polyclonal antibodies that are specifically immunoreactive with WISE/SOST-like peptides such as those exemplified by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 15-18, 20-82, 85-87, 91, 93, 95, 98, 101, 103, 105, 109-217 and not with other random proteins. This selection may be achieved by subtracting out antibodies that cross-react with other molecules. A variety of immunoassay formats may be used to select antibodies specifically immunoreactive with a particular protein. For example, solid-phase ELISA immunoassays are routinely used to select antibodies specifically immunoreactive with a protein (see, e.g., Harlow & Lane, Antibodies, A Laboratory Manual (1988) for a description of immunoassay formats and conditions that can be used to determine specific immunoreactivity).

The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same as measured using a BLAST or BLAST 2.0 sequence comparison algorithms with default parameters described below, or by manual alignment and visual inspection (see, e.g., NCBI web site http://www.ncbi.nlm.nih.gov/BLAST/ or the like). Such sequences are said to be “substantially identical” when they have about 60% identity, preferably 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or higher identity over a specified region, once compared and aligned for maximum correspondence over a comparison window or designated region. This definition also refers to, or may be applied to, the complement of a test sequence. The definition also includes sequences that have deletions and/or additions, as well as those that have substitutions, as well as naturally occurring, e.g., polymorphic or allelic variants, and man-made variants. As described below, the preferred algorithms can account for gaps and the like.

For sequence comparison, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are entered into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. Preferably, default program parameters can be used, or alternative parameters can be designated. The sequence comparison algorithm then calculates the percent sequence identities for the test sequences relative to the reference sequence, based on the program parameters.

A “comparison window”, as used herein, includes reference to a segment of one of the number of contiguous positions selected from the group typically of from 20 to 600, usually about 50 to about 200, more usually about 100 to about 150 in which a sequence may be compared to a reference sequence of the same number of contiguous positions after the two sequences are optimally aligned. Methods of alignment of sequences for comparison are well-known in the art. Optimal alignment of sequences for comparison can be conducted, e.g., by the local homology algorithm of Smith & Waterman, Adv. Appl. Math. 2:482 (1981), by the homology alignment algorithm of Needleman & Wunsch, J. Mol. Biol. 48:443 (1970), by the search for similarity method of Pearson & Lipman, Proc. Nat'l. Acad. Sci. USA 85:2444 (1988), by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Dr., Madison, Wis.), or by manual alignment and visual inspection (see, e.g., Current Protocols in Molecular Biology (Ausubel et al., eds. 1995 supplement)).

Preferred examples of algorithms that are suitable for determining percent sequence identity and sequence similarity include the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al., Nuc. Acids Res. 25:3389-3402 (1977) and Altschul et al., J. Mol. Biol. 215:403-410 (1990). BLAST and BLAST 2.0 are used, with the parameters described herein, to determine percent sequence identity for the nucleic acids and proteins of the invention. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al., supra). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Cumulative scores are calculated using, e.g., for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penalty score for mismatching residues; always <0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative-scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a wordlength (W) of 11, an expectation (E) of 10, M=5, N=−4 and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength of 3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff & Henikoff, Proc. Natl. Acad. Sci. USA 89:10915 (1989)) alignments (B) of 50, expectation (E) of 10, M=5, N=−4, and a comparison of both strands.

The BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin & Altschul, Proc. Nat'l. Acad. Sci. USA 90:5873-5787 (1993)). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.2, more preferably less than about 0.01, and most preferably less than about 0.001. Log values may be large negative numbers, e.g., 5, 10, 20, 30, 40, 40, 70, 90, 110, 150, 170, etc.

The phrase “conditions suitable for protein binding” refers to those conditions (in terms of salt concentration, pH, detergent, protein concentration, temperature, etc.) which allow for binding to occur between a protein and its binding partner in solution. The conditions are not so lenient that a significant amount of nonspecific protein binding occurs.

As used herein, the term “developmental regulators” refers to molecules associated with the Wnt and BMP signaling pathways. Specifically, the term refers to the ligands and receptors responsible for regulating the Wnt and BMP signaling pathways including, but not limited to, LRP5, LRP6, BMP2, BMP4, BMP6, and BMP7. For example, several of these developmental regulators are provided by SEQ ID NOs: 1-217 as presented in the present application.

DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

FIG. 1 graphically illustrates inhibition of SOST association with LRP6. Relative LRP6 binding to variants of SOST was measured following immunoprecipitation. SOST variants M1, M2, M3, and M8 significantly exhibited reduced binding to LRP6 compared to wild type SOST.

DETAILED DESCRIPTION I. Introduction

The present invention provides compositions and methods of using certain protein-based renal therapeutic agents that surprisingly prevent, inhibit, delay or alleviate the progressive loss of renal function. In a preferred embodiment, the present invention is suitable for treatment of renal disease.

In some forms, renal disease is caused by aberrant signal transduction during kidney development. The kidney develops from the ureteric bud, extending out from a pre-existing epithelial tube, giving rise to the branched collecting duct system while the surrounding metanephric mesenchyme undergoes mesenchymal-epithelial transition to form the proximal parts of the nephron. Signaling by members of the Wnt, BMP and FGF protein families, mediate this nephrogenesis by adjusting the balance between the ureteric bud epithelium, stromal and nephrogenic tissues. Inappropriate alteration of the balance of these signaling pathways, gives rise to renal disease. For example, over-activation of the Wnt pathway leads to cancer development (e.g. Wilms tumor), while inhibition of BMP signaling results in nephronic degeneration, both ultimately leading to renal failure.

WISE and/or SOST signaling also influences mature kidney tissue homeostasis, particularly in the case of renal damage or disease. In certain embodiments of the present invention, renal disease or damage is mitigated or reversed by administering to a patient antibodies that perturb or block the association of WISE and/or SOST to its receptor molecules in vivo. For example, administration of antibodies that mimic the WISE and/or SOST association with LRP5 or LRP6 may be used to subdue over-activated Wnt signaling in the treatment of kidney cancer. Alternatively, the association of WISE and/or SOST with BMP6, BMP7, and/or BMP2 may be inhibited to allow BMP signaling, which may result in protection from nephronic injury and/or promotion of nephronic regeneration.

II. Biological Assays of the Invention

The phrase “nephronic degeneration” refers to deterioration of an individual's kidney in which kidney or renal function is diminished as result of tissue necrosis or apoptosis by at least 5% preferably 10%, 15%, 20%, 25%, 30%, 40% 50% or more from the range of normal values medically determined for the individual. Nephronic degeneration can result from physical insult, chemical insult, or disease. The presence of nephronic degeneration can be measured by assays well known to those of ordinary skill of the art, such as elevation of serum creatinine levels or decrease in creatinine clearance (see, Brenner and Lazarus (1994), in HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 13th edition, Isselbacher et al., eds., McGraw Hill Text, N.Y.). Preferably a decrease of 5%, more preferably 10%, 15%, 20%, 25%, 30%, 40%, 50% or more of creatinine clearance compared to normal levels marks nephronic degeneration. Likewise, a 5% elevation of serum creatinine levels, more preferably 10%, 15%, 20%, 25%, 30%, 40%, 50% or more compared to normal levels indicates nephronic degeneration.

The phrase “nephron protection” refers to an in vivo phenomenon that protects against and prevents degeneration of nephronic or renal function caused by physical insult, chemical insult, or disease. As such, nephron protection refers to an in vivo phenomenon that inhibits elevation of serum creatinine levels or decrease in creatinine clearance by at least 5% preferably 10%, 15%, 20%, 25%, 30%, 40% 50% or more from the range of elevated values medically determined for the individual. Nephron protection also encompasses regeneration or repair of degenerate nephronic function caused by tissue necrosis or apoptosis resulting from physical insult, chemical insult, or disease. The regeneration or repair of degenerate nephronic function can be measured by assays well known to those of ordinary skill of the art, such as serum creatinine levels or creatinine clearance. Preferably an increase of 5%, more preferably 10%, 15%, 20%, 25%, 30%, 40%, 50% or more of creatinine clearance compared to normal levels marks nephronic protection. Likewise, a 5% decrease of serum creatinine levels, more preferably a 10%, 15%, 20%, 25%, 30%, 40%, 50% or more compared to normal levels indicates nephronic protection.

Assays of renal function are well known to those of ordinary skill of the art and include, without being limited to, rates of increase in Blood Urea Nitrogen (BUN) levels, rates of increase in serum creatinine, static measurements of BUN, static measurements of serum creatinine, glomerular filtration rates (GFR), ratios of BUN/creatinine, serum concentrations of sodium (Na+), urine/plasma ratios for creatinine, urine/plasma ratios for urea, urine osmolality, daily urine output, and the like (see, Brenner and Lazarus (1994), in HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 13th edition, Isselbacher et al., eds., McGraw Hill Text, N.Y.). Exemplary normal levels are as follows: serum creatinine levels of 0.8 to 1.4 mg/dL; BUN levels of 5 to 20 mg/dL; GFR score of 90 mL/min or more; BUN/Creatinine ratio of 10:1 to 20:1 and up to 30:1 in infants under 12 months of age; and serum sodium levels of 135 to 145 mEq/L. A skilled artisan will recognize that the normal ranges may vary with age, muscle mass, gender, weight, body surface area, and other characteristics. An “improvement” in one of the assays of renal function refers to an increase or decrease in level that is closer to the normal range. For example, a 10% improvement of a serum creatinine level of 0.2 mg/dL would be a serum creatinine level of 0.22 mg/dL, while a 10% improvement of a serum creatinine level of 3.0 mg/dL would be a serum creatinine level of 2.7 mg/dL.

III. Therapeutic Compositions

The present invention is directed to compositions and methods that regulate the interaction between SOST and WISE proteins with their natural receptors, particularly LRP5, LRP6, and BMP molecules. The renal therapeutic agents of the invention include, but are not limited to, peptides, proteins, antibodies, and small molecules derived from the WISE/SOST and LRP/BMP families and resultantly regulate Wnt and BMP signaling. For example, any peptide of at least 20, preferably 25, 30, 35, 40, 50 or more amino acids encoded by SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 15-18, 20-82, 85-87, 91, 93, 95, 98, 101, 103, 105, 109-217, or any fragment of any sequence thereof, may be used to raise antibodies, derive peptides, or derive small molecules suitable for antagonizing the interaction between SOST and WISE proteins with their natural receptors.

Such peptides may provide the basis of therapeutics by their inherent properties. For example, as inhibitors of renal damage, blocking peptides that antagonize the interaction between SOST and WISE proteins with their natural receptors may be useful. Further, peptides that activate SOST and WISE natural receptors by mimicking the necessary interaction between SOST or WISE and their natural receptors may also be useful. Exemplary antagonizing or activating peptides may include those provided by SEQ ID NOS: 21-82 or fragments of SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 15-18, 20, 85-87, 91, 93, 95, 98, 101, 103, 105, 109-217.

A. Peptides and Proteins

Proteins and peptides useful to the invention may be isolated from natural sources, prepared synthetically or recombinantly, or any combination of the same using techniques well known to those of skill in the art. Generally, any purification protocol suitable for isolating proteins and known to those of skill in the art can be used. For example, affinity purification, column chromatography techniques, precipitation protocols and other methods for separating proteins may be used (see, e.g., Scopes, Protein Purification: Principles and Practice (1982); and U.S. Pat. No. 4,673,641). Further, peptides may be produced synthetically using solid phase techniques and other techniques known to those skilled in the art (see, Barany, G. and Merrifield, R. B. Solid Phase Peptide Synthesis in PEPTIDES, Vol. 2, Academic Press, New York, N.Y., pp. 100-118 (1980)). Peptides and proteins of the invention may also be available commercially, or may be produced commercially.

B. Antibodies

The renal therapeutic agents of the present invention may be antibodies that recognize developmental regulator proteins, polypeptides, amino acid sequences, or fragments thereof. Suitable antibodies include those that recognize the WISE/SOST and LRP/BMP families and resultantly regulate Wnt and BMP signaling, such as those described in U.S. application Ser. No. 11/508,701 and incorporated herein by reference. For example, antibodies of the invention will recognize proteins or amino acid sequences encoding developmental regulators or fragments thereof, such as, but not limited to, those provided by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 15-18, 20-82, 85-87, 91, 93, 95, 98, 101, 103, 105, 109-217. More preferably, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of or encoded by SEQ ID NOS. 2, 4, 6, 8, 10, 12, 14, 15-18, 20, 85-87, 91, 93, 95, 98, 101, 103, 105, and 109-217; more preferably SEQ ID NOS. 90-108, 215, and 216; more preferably, SEQ ID NOS. 19-89, 15-18, and 217; more preferably, SEQ ID NOS. 90-93, 215, and 216; more preferably, SEQ ID NOS. 15-20 and 217; more preferably, SEQ ID NOS. 92, 93, and 215; more preferably SEQ ID NOS. 15-18 and 217; more preferably, SEQ ID NOS. 15-18. Alternatively, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of positions 50-62, 68-80, or 83-98 of SEQ ID NOS. 20, and 215-217.

When the above family of amino acid sequences, including WISE and SOST, are allowed to bind to their natural receptors, renal regeneration is repressed. When the above-mentioned family of amino acid sequences are prevented from binding to their natural receptors, renal regeneration will increase. Thus, the present invention relates to tools and methods used to inhibit or mimic the binding of the WISE/SOST family to their natural receptors.

1. Antigen Specificity and Production

The present invention provides at least one antibody that inhibits interaction between Wnt or BMP antagonistic ligands (developmental regulators) with LRP or BMP receptors, thus promoting constitutive Wnt or BMP signaling and renal regeneration. Suitable antibodies are obtained by immunizing a host animal with peptides, or antigens, that are all or a portion of the subject protein of the presently claimed invention. The antigen may be the complete protein, or fragments and derivatives thereof. For example, a suitable antigen may have at least 75%, 80%, 85%, 90%, 95%, 98%, 99% or 100% identity to at least 5, 8, 10, 12, 15, 20, or 25 contiguous amino acids of a protein encoded by SEQ ID NOS: 2, 4, 6, 8, 10, 12, 14, 15-18, 20-82, 85-87, 91, 93, 95, 98, 101, 103, 105, 109-217. More preferably, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of or encoded by SEQ ID NOS. 2, 4, 6, 8, 10, 12, 14, 15-18, 20, 85-87, 91, 93, 95, 98, 101, 103, 105, and 109-217; more preferably SEQ ID NOS. 90-108, 215, and 216; more preferably, SEQ ID NOS. 19-89, 15-18, and 217; more preferably, SEQ ID NOS. 90-93, 215, and 216; more preferably, SEQ ID NOS. 15-20 and 217; more preferably, SEQ ID NOS. 92, 93, and 215; more preferably SEQ ID NOS. 15-18 and 217; more preferably, SEQ ID NOS. 15-18. Alternatively, the antibody specifically binds a peptide having at least 75%, 80%, 85%, 90%, 95%, 99% or more identity to at least 5, 8, 10, 15, 20 or more contiguous amino acids of positions 50-62, 68-80, or 83-98 of SEQ ID NOS. 20, and 215-217.

Some exemplary embodiment of the present invention includes antibodies that inhibit, block, or otherwise interfere with the specific binding of an LRP or BMP molecule to a Wnt or BMP antagonistic ligand. A skilled artisan will recognize that an antigen may be selected to generate an antibody that interferes by specifically binding to the LRP or BMP molecule or by specifically binding to the Wnt or BMP antagonistic ligand. The selected antigen will result in an antibody that will specifically bind to WISE-like or SOST-like proteins and prevent the interaction of WISE-like or SOST-like proteins with LRP5, LRP6, BMP2, BMP6, or BMP7. in alternative examples, a selected antigen will result in an antibody that will specifically bind to LRP5, LRP6, or BMP molecules and prevent the interaction with WISE-like or SOST-like proteins.

Suitable amounts of well-characterized antigen for production of antibodies can be obtained using standard techniques known in the art such as, but not limited to, cloning or synthetic synthesis. Antigenic proteins can be obtained from transfected cultured cells that overproduce the antigen of interest. For example, expression vectors that have nucleotide sequences encoding an antigen of interest can be constructed, transfected into cultured cells, and then the antigen can be subsequently isolated using methods well-known to those skilled in the art (see, Wilson et al., J. Exp. Med. 173:137, 1991; Wilson et al., J. Immunol. 150:5013, 1993). Alternatively, DNA molecules encoding an antigen of choice can be obtained by synthesizing DNA molecules using mutually priming long oligonucleotides (see, Ausubel et al., (eds.), Current Protocols In Molecular Biology, pages 8.2.8 to 8.2.13, 1990; Wosnick et al., Gene 60:115, 1987; and Ausubel et al. (eds.), Short Protocols In Molecular Biology, 3rd Edition, pages 8-8 to 8-9, John Wiley & Sons, Inc., 1995). As a skilled artisan will recognize, established techniques using the polymerase chain reaction provide the ability to synthesize antigens (Adang et al., Plant Molec. Biol. 21:1131, 1993; Bambot et al., PCR Methods and Applications 2:266, 1993; Dillon et al., “Use of the Polymerase Chain Reaction for the Rapid Construction of Synthetic Genes,” in METHODS IN MOLECULAR BIOLOGY, Vol. 15: PCR PROTOCOLS: CURRENT METHODS AND APPLICATIONS, White (ed.), pages 263 268, Humana Press, Inc. 1993). Once produced, the antigen of choice is used to generate antigen specific antibodies.

2. Antibody Production

The present invention provides antibodies as renal therapeutic agents. It is envisioned that such antibodies include, but are not limited to, polyclonal, monoclonal, humanized, part human, or fragments thereof. A skilled artisan will appreciate the benefits and disadvantages of the type of antibody used for therapeutic treatment and will further recognize the selection is dependent upon the intended use.

a. Polyclonal Antibodies

Means for preparing and characterizing polyclonal antibodies are well known to those skilled in the art (see, e.g., Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, 1988; incorporated herein by reference). For example, for the preparation of polyclonal antibodies, the first step is immunization of the host animal with the target antigen, where the target antigen will preferably be in substantially pure form, with less than about 1% contaminant. The antigen may include the complete target protein, fragments, or derivatives thereof. To prepare polyclonal antisera an animal is immunized with an antigen of interest, and antisera is collected from that immunized animal. A wide range of animal species can be used for the production of antisera. Typically the animal used for production of anti-antisera is a rabbit, mouse, rat, hamster, guinea pig or goat. Because of the relatively large blood volume of rabbits, a rabbit is a preferred choice for the production of polyclonal antibodies.

The amount of antigen used in the production of polyclonal antibodies varies upon the nature of the antigen as well as the animal used for immunization. A variety of routes can be used to administer the antigen of choice; subcutaneous, intramuscular, intradermal, intravenous, intraperitoneal and intrasplenic. The production of polyclonal antibodies may be monitored by sampling blood of the immunized animal at various points following immunization. A second, booster injection, may also be given. The process of boosting and titering is repeated until a suitable titer is achieved. When a desired titer level is obtained, the immunized animal can be bled and the serum isolated and stored. The animal can also be used to generate monoclonal antibodies, as is well known to those skilled in the art.

The immunogenicity of a particular composition can be enhanced by the use of non-specific stimulators of the immune response, known as adjuvants. Exemplary adjuvants include complete Freund's adjuvant, a non-specific stimulator of the immune response containing killed Mycobacterium tuberculosis; incomplete Freund's adjuvant; and aluminum hydroxide adjuvant.

It may also be desired to boost the host immune system, as may be achieved by associating the antigen with, or coupling the antigen to, a carrier. Exemplary carriers include keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA). Other albumins such as ovalbumin, mouse serum albumin or rabbit serum albumin can also be used as carriers. As is also known in the art, a given composition may vary in its immunogenicity.

b. Monoclonal Antibodies

Monoclonal antibodies (Mabs) may be readily prepared through use of well-known techniques to those skilled in the art, such as those exemplified in U.S. Pat. No. 4,196,265, incorporated herein by reference. Typically, this technique involves immunizing a suitable animal with the selected antigen. The antigen is administered in a manner effective to stimulate antibody-producing cells. Rodents such as mice and rats are preferred animals, however, the use of rabbit, sheep and frog cells is also possible.

By way of example, following immunization the somatic cells with the potential for producing antigen specific antibodies, specifically B lymphocytes (B cells), are selected for use in the MAb generating protocol. These cells may be obtained from biopsied spleens, tonsils or lymph nodes, or from a peripheral blood sample. Spleen cells and peripheral blood cells are preferred, the former because they are a rich source of antibody-producing cells that are in the dividing plasmablast stage, and the latter because peripheral blood is easily accessible. Often, a panel of animals will have been immunized and the spleen of the animal with the highest antibody titer will be removed and the spleen lymphocytes obtained by homogenizing the spleen with a syringe. Typically, a spleen from an immunized mouse contains approximately 5×10⁷ to 2×10⁸ lymphocytes.

The anti-antigen antibody-producing B lymphocytes from the immunized animal are then fused with cells of an immortal myeloma cell, generally one of the same species as the animal that was immunized. Myeloma cell lines suited for use in hybridoma-producing fusion procedures preferably are non-antibody-producing, have high fusion efficiency, and enzyme deficiencies that render them incapable of growing in certain selective media which support the growth of only the desired fused cells (hybridomas).

Any one of a number of myeloma cells may be used, as are known to those of skill in the art (Goding, pp. 65 66, 1986; Campbell, pp. 75 83, 1984; each incorporated herein by reference). For example, where the immunized animal is a mouse, one may use P3-X63/Ag8, X63-Ag8.653, NS1/1.Ag 41, Sp210-Ag14, FO, NSO/U, MPC-11, MPC11-X45-GTG 1.7 and S194/5XX0 Bul; for rats, one may use R210.RCY3, Y3-Ag 1.2.3, IR983F, 4B210 or one of the above listed mouse cell lines; and U-266, GM1500-GRG2, LICR-LON-HMy2 and UC729-6, are all useful in connection with human cell fusions.

The heterogeneous cell population may be cultured in the presence of a selection medium to select out the hybridoma cells. A suitable selection medium includes an inhibitor of de novo synthesis, such as aminopterin in HAT medium, methotrexate in HMT medium, or azaserine in AzaH medium plus the necessary purine and/or pyrimidine salvage precursors (i.e. hypoxanthine and thymidine in HAT or HMT media; hypoxanthine in AzaH medium). Only cells capable of operating nucleotide salvage pathways are able to survive in the selection medium. The myeloma cells are defective in key enzymes of the salvage pathway, e.g., hypoxanthine phosphoribosyl transferase (HPRT), and cannot survive. The B cells can operate this pathway, but they have a limited life span in culture and generally die within about two weeks. Therefore, the only cells that can survive in the selective media are those hybrids formed from myeloma and B cells (hybridomas).

Culturing provides a population of hybridomas from which specific hybridomas are selected. Typically, selection of hybridomas is performed by culturing the cells by single-clone dilution in microtiter plates, followed by testing the individual clonal supernatants (after about two to three weeks) for the desired anti-antigen reactivity. The assay should be sensitive, simple and rapid, such as radioimmunoassays, enzyme immunoassays, cytotoxicity assays, plaque assays, dot immunobinding assays, and the like.

The selected hybridomas would then be serially diluted and cloned into individual anti-antigen antibody-producing cell lines, which clones can then be propagated indefinitely to provide MAbs. The cell lines may be exploited for MAb production in two basic ways. A sample of the hybridoma can be injected (often into the peritoneal cavity) into a histocompatible animal of the type that was used to provide the somatic and myeloma cells for the original fusion. The injected animal develops tumors secreting the specific monoclonal antibody produced by the fused cell hybrid. The body fluids of the animal, such as serum or ascites fluid, can then be tapped to provide MAbs in high concentration. The individual cell lines could also be cultured in vitro, where the MAbs are naturally secreted into the culture medium from which they can be readily obtained in high concentrations.

MAbs produced by either means will generally be further purified, e.g., using filtration, centrifugation and various chromatographic methods, such as HPLC or affinity chromatography, all of which purification techniques are well known to those of skill in the art. These purification techniques each involve fractionation to separate the desired antibody from other components of a mixture. Analytical methods particularly suited to the preparation of antibodies include, for example, protein A-Sepharose and/or protein G-Sepharose chromatography.

c. Humanized Antibodies

Also of interest are humanized antibodies. Methods of humanizing antibodies are known in the art. The humanized antibody may be the product of an animal having transgenic human immunoglobulin constant region genes (see for example International Patent Applications WO 90/10077 and WO 90/04036, both incorporated herein by reference). Alternatively, the antibody of interest may be engineered by recombinant DNA techniques to substitute the CH1, CH2, CH3, hinge domains, and/or the framework domain with the corresponding human sequence (see WO 92/02190 and incorporated herein by reference).

The use of 1 g cDNA for construction of chimeric immunoglobulin genes is known in the art (Liu et al. P.N.A.S. 84:3439, 1987 and incorporated herein by reference). mRNA is isolated from a hybridoma or other cell producing the antibody and used to produce cDNA. The cDNA of interest may be amplified by the polymerase chain reaction using specific primers (see U.S. Pat. Nos. 4,683,195 and 4,683,202, both incorporated herein by reference). Alternatively, a library is made and screened to isolate the sequence of interest. The DNA sequence encoding the variable region of the antibody is then fused to human constant region sequences. The sequences of human constant region genes may be found in Kabat et al. Sequences of Proteins of Immunological Interest, N.I.H. publication no. 91-3242, 1991 and incorporated herein by reference. Human C region genes are readily available from known clones. The chimeric, humanized antibody is then expressed by conventional methods known to those of skill in the art.

d. Antibody Fragments

Antibody fragments, such as Fv, F(ab′)₂ and Fab may be prepared by cleavage of the intact protein, e.g. by protease or chemical cleavage. Alternatively, a truncated gene is designed. For example, a chimeric gene encoding a portion of the F(ab′)₂ fragment would include DNA sequences encoding the CH1 domain and hinge region of the H chain, followed by a translational stop codon to yield the truncated molecule. The following patents and patent applications are specifically incorporated herein by reference for the preparation and use of functional, antigen-binding regions of antibodies, including scFv, Fv, Fab′, Fab and F(ab′)₂ fragments: U.S. Pat. Nos. 5,855,866; 5,965,132; 6,051,230; 6,004,555; and 5,877,289.

Also contemplated are diabodies, which are small antibody fragments with two antigen-binding sites. The fragments may include a heavy chain variable domain (V_(H)) connected to a light chain variable domain (V_(L)) in the same polypeptide chain (V_(H) V_(L)). By using a linker that is too short to allow pairing between the two domains on the same chain, the domains are forced to pair with the complementary domains of another chain and create two antigen-binding sites. Techniques for generating diabodies are well known to those of skill in the art and are also described in EP 404,097 and WO 93/11161, each specifically incorporated herein by reference. Also, linear antibodies, which can be bispecific or monospecific, may include a pair of tandem Fd segments (V_(H) C_(H1)—V_(H) C_(H1)) that form a pair of antigen binding regions may be useful to the invention as described in Zapata et al. (1995), and incorporated herein by reference.

C. Compositions

The renal therapeutic agents contemplated herein can be expressed from intact or truncated genomic or cDNA or from synthetic DNAs in prokaryotic or eukaryotic host cells by techniques well known to those of skill in the art. Exemplary host cells include, without limitation, prokaryotes including E. coli, or eukaryotes including yeast, Saccharomyces, insect cells, or mammalian cells, such as CHO, COS or BSC cells. One of ordinary kill in the art will appreciate that other host cells can be used to advantage.

The term “construct” as used herein refers to a nucleic acid sequence containing at least one polynucleotide encoding a polypeptide of the invention operably linked or fused to additional nucleic acids. Such constructs include vectors, plasmids, and expression cassettes encoding at least one polynucleotide encoding a polypeptide of the invention. It is also envisioned that constructs could be polynucleotides encoding a polypeptide of the invention fused to other protein coding sequence to generate Fusion proteins as known to those of skill in the art.

Constructs can be inserted into mammalian host cells by methods known to those of skill in the art including, but not limited to, electroporation, transfection, microinjection, micro-vessel transfer, particle bombardment, biolistic particle delivery, liposome mediated transfer and other methods described in Current Protocols in Cell Biology, Unit 20, pub. John Wiley & Sons, Inc., 2004 and incorporated herein by reference.

III. Therapeutic Uses

A. Subjects for Treatment

Renal therapeutic agents of the invention may be used in subjects that have received renal injury, or those at risk of chronic renal failure. As used herein, a subject is said to be in, or at risk of, chronic renal failure, or at risk of the need for renal replacement therapy (i.e., chronic hemodialysis, continuous peritoneal dialysis, or kidney transplantation), if the subject is reasonably expected to suffer a progressive loss of renal function associated with progressive loss of functioning nephron units. Whether a particular subject is in, or at risk of, chronic renal failure is a determination which may routinely be made by one of ordinary skill in the relevant medical or veterinary art. Subjects in, or at risk of, chronic renal failure, or at risk of the need for renal replacement therapy, include but are not limited to the following: subjects which may be regarded as afflicted with chronic renal failure, end-stage renal disease, chronic diabetic nephropathy, hypertensive nephrosclerosis, chronic glomerulonephritis, hereditary nephritis, and/or renal dysplasia; subjects having a biopsy indicating glomerular hypertrophy, tubular hypertrophy, chronic glomerulosclerosis, renal cell carcinoma, and/or chronic tubulointerstitial sclerosis; subjects having an ultrasound, MRI, CAT scan, or other non-invasive examination indicating renal fibrosis; subjects having an unusual number of broad casts present in urinary sediment; subjects having a GFR which is chronically less than about 50%, and more particularly less than about 40%, 30% or 20%, of the expected GFR for the subject; human male subjects weighing at least about 50 kg and having a GFR which is chronically less than about 50 ml/min, and more particularly less than about 40 ml/min, 30 ml/min or 20 ml/min; human female subjects weighing at least about 40 kg and having a GFR which is chronically less than about 40 ml/min, and more particularly less than about 30 ml/min, 20 ml/min or 10 ml/min; subjects possessing a number of functional nephron units which is less than about 50%, and more particularly less than about 40%, 30% or 20%, of the number of functional nephron units possessed by a healthy but otherwise similar subject; subjects which have a single kidney; and subjects which are kidney transplant recipients.

The methods and compositions of the present invention may be utilized for any mammalian subject. Such mammalian subjects include, but are not limited to, human subjects or patients. Exemplary subjects may also include domesticated mammals (e.g., dogs, cats, horses), mammals with significant commercial value (e.g., dairy cows, beef cattle, sporting animals), mammals with significant scientific value (e.g., captive or free specimens of endangered species), or mammals which otherwise have value.

B. Excipients

The renal therapeutic agents of the invention, alone or conjugated, may be formulated according to methods known to those skilled in the art to prepare pharmaceutically useful compositions, whereby the therapeutic agents are combined in a mixture with a pharmaceutically acceptable carrier or excipient. A composition is said to be a “pharmaceutically acceptable carrier” if its administration can be tolerated by a recipient patient and preserves the activity of the active component, in this case the renal therapeutic agent. Exemplary carriers include, but not are limited to, saline, buffered saline, dextrose, water, glycerol, ethanol, and combinations thereof. The formulation should suit the mode of administration. Other suitable carriers are well known to those skilled in the art (see, REMINGTON'S PHARMACEUTICAL SCIENCES, 19th Ed., 1995). Upon formulation, the antibody or immunoconjugate solutions will be administered in a manner compatible with the dosage formulation and in such amount as is therapeutically effective.

C. Dosage

In general, the dosage of administered renal therapeutic agents will vary depending upon such factors as the patient's age, weight, height, sex, general medical condition and previous medical history. For example, it is typically desirable to provide the recipient with a dosage of an antibody component, which is in the range of from about 1 pg/kg to 10 mg/kg (amount of agent/body weight of patient), although a lower or higher dosage also may be administered as circumstances dictate. Range finding studies may be conducted to determine appropriate dosage by techniques known to those skilled in the art and as described in Current Protocols in Pharmacology, Unit 10, pub. John Wiley & Sons, 2003 and incorporated herein by reference. A skilled artisan will recognize the therapeutically effective amount for each active compound may vary with factors including, but not limited to, the activity of the compound used, stability of the active compound in the recipient's body, the total weight of the recipient treated, the route of administration, the ease of absorption, distribution, and excretion of the active compound by the recipient, the age and sensitivity of the recipient to be treated, the type of tissue, and the like.

For purposes of therapy, renal therapeutic agents are administered to a patient in a therapeutically effective amount in a pharmaceutically acceptable carrier. In this regard, a “therapeutically effective amount” is one that is physiologically significant. An agent is physiologically significant if its presence results in a detectable change in the physiology of a recipient patient. In the present context, an agent is physiologically significant if its presence results in a clinically significant improvement in an assay of renal function when administered to a mammalian subject (e.g., a human patient). Such assays of renal function are well known to those of skill in the art and include, without being limited to, rates of increase in Blood Urea Nitrogen (BUN) levels, rates of increase in serum creatinine, static measurements of BUN, static measurements of serum creatinine, glomerular filtration rates (GFR), ratios of BUN/creatinine, serum concentrations of sodium (Na+), urine/plasma ratios for creatinine, urine/plasma ratios for urea, urine osmolality, daily urine output, and the like (see, Brenner and Lazarus (1994), in HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, 13th edition, Isselbacher et al., eds., McGraw Hill Text, N.Y.)

Additional pharmaceutical methods may be employed to control the duration of action of an antibody in a therapeutic application. Control release preparations can be prepared through the use of polymers to complex or adsorb the renal therapeutic agent. For example, biocompatible polymers include matrices of poly(ethylene-co-vinyl acetate) and matrices of a polyanhydride copolymer of a stearic acid dimer and sebacic acid (Sherwood et al., Bio/Technology 10:1446, 1992). The rate of release of an agent from such a matrix depends upon the molecular weight of the protein, the amount of agent within the matrix, and the size of dispersed particles (Saltzman et al., Biophys. J. 55:163, 1989; Sherwood et al., Bio/Technology 10:1446, 1992). Other solid dosage forms are described in REMINGTON'S PHARMACEUTICAL SCIENCES, 19th ed. (1995) and can be prepared by techniques known to those skilled in the art.

D. Routes of Administration

Administration of renal therapeutic agents to a patient can be intravenous, intraarterial, intraperitoneal, intramuscular, subcutaneous, intrapleural, intrathecal, by perfusion through a regional catheter, or by direct intralesional injection. When administering therapeutic proteins by injection, the administration may be by continuous infusion or by single or multiple boluses. Intravenous injection provides a useful mode of administration due to the thoroughness of the circulation in rapidly distributing antibodies.

E. Methods for Testing Renal Therapeutic Agents

The renal therapeutic agents of the present invention may be tested in animal models of chronic renal failure or nephronic degeneration. Mammalian models of nephronic degeneration in, for example, mice, rats, guinea pigs, cats, dogs, sheep, goats, pigs, cows, horses, and non-human primates, may be created by causing an appropriate direct or indirect injury or insult to the renal tissues of the animal. For example, animal models of nephronic degeneration may be created by administering cisplatin, which causes nephrotoxicity and reduced creatinine clearance. Animal models of nephronic degeneration may also be created by performing a partial (e.g., ⅚) nephrectomy which reduces the number of function nephron units to a level which initiates compensatory renal hypertrophy, further nephron loss, and the progressive decline in renal function (see, Vukicevic, et al. J. Bone Mineral Res. 2:533, 1987). Alternatively, animal models of renal cell carcinoma may be generated by subcapsular renal injection of renal carcinoma (RENCA) cells that results in the development of primary tumors with subsequent development of metastases in the lungs, lymph nodes, and spleen (see, Hillman, G. G., Droz, J., and Haas, G. H. In Vivo, 8: 77-80, 1994). The above-described animal models may be generated by techniques well-known to those of skill in the art.

The renal therapeutic agents may be administered to the above-described animal models and markers of renal function can be monitored (see, Examples 1-3). Preferably kidney function is determined using markers of renal function such as Blood Urea Nitrogen (BUN) levels, serum creatinine levels, or glomerular filtration. Exemplary renal therapeutic agents will result in a decrease of BUN or serum creatinine levels or increase in glomerular filtration rate compared to control animals. Control animals will be animal models treated with a control solution not containing the renal therapeutic agent being tested, preferably a non-irritating buffer solution or other carrier.

IV. Kits

The present invention provides articles of manufacture and kits containing materials useful for treating the pathological conditions described herein. The article of manufacture may include a container of a medicament as described herein with a label. Suitable containers include, for example, bottles, vials, and test tubes. The containers may be formed from a variety of materials such as glass or plastic. The container holds a composition having an active agent which is effective for treating, for example, diseases characterized by nephronic degeneration. Alternatively, the container may hold a composition that includes a nephronic degeneration-inducing agent. The active agent in the composition is a renal therapeutic agent of the invention, including a peptide, protein, antibody, small molecule, or an agent such as a vector or cell preparation capable of allowing production of a renal therapeutic agent in vivo. The label on the container indicates that the composition is used for treating nephronic degenerative diseases, or malignant diseases, and may also indicate directions for administration and monitoring techniques, such as those described above.

The kit of the invention includes the container described above and a second container, which may include a pharmaceutically acceptable diluent. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, syringes, and package inserts with instructions for use.

EXAMPLES

As can be appreciated from the disclosure provided above, the present invention has a wide variety of applications. Accordingly, the following examples are offered for illustration purposes and are not intended to be construed as a limitation on the invention in any way. Those of skill in the art will readily recognize a variety of non-critical parameters that could be changed or modified to yield essentially similar results.

Example 1 WISE/SOST Antibody Production

SOST and Wise both share the same gene structure, and produce a secreted protein whose second exon encodes a cystein knot. Molecular dissection of SOST at the amino acid level revealed putative LRP⅚ binding sites located in the first arm of the cystein knot. An immunoprecipitation assay of Flag tagged SOST variants and LRP6 was used to confirm which of these sites were necessary for LRP⅚ binding. Variants of SOST were generated with mutations at positions 60-62 (M1), 78-81 (M2), 89-90 (M3), 100-103 (M4), 140-143 (M7), and 162-166 (M8s). An immunoprecipitated western blot of Flag tagged SOST was mixed with LRP6-IgG and was quantified using phosphor-imager and its software ImageQuant. SOST variants M1, M2 and M3 showed a significant loss of binding ability to LRP6 (FIG. 1), thus indicating potential sites for mediating the block between SOST and its natural binding partners including LRP⅚, BMP6, and BMP7.

In order to block the binding of SOST to LRP ⅚, BMP6, or BMP7 inhibitory antibodies were generated that recognize the altered amino acids of SOST variants M1, M2, and M3. Specific epitopes targeting these amino acids were identified using antigenic hydrophobic plots. These plots revealed that the best sites for generation of an antibody were between amino acids 50-62, 68-80, and 83-98 of SEQ ID NO. 215 and 217. The resultant peptides selected as antigens to produce antibodies are listed in SEQ ID NOS 15-18 and were used to generate monoclonal antibodies.

The peptides of SEQ ID NO 15-18 were used to immunize mice. Following immunization, B lymphocytes (B cells) were obtained from peripheral blood samples. The B cells from the immunized mice were then fused with murine myeloma cells to produce hybridomas. The cells were cultured in HAT medium with hypoxanthine and thymidine to select out the hybridoma cells. Hybridomas were then cultured by single-clone dilution in microtiter plates, followed by ELISA testing of the individual clonal supernatants for desired anti-antigen reactivity. There were 27 ELISA positive monoclonal antibodies generated against SOST.

Example 2 Acute Renal Failure Treatment

Acute renal failure manifests itself immediately following renal insult or injury. Therapeutics of the present invention may be analyzed for use as a treatment for preventing or reversing acute renal failure.

Mice subjected to partial nephrectomies or decapsulation may be used as models of nephronic degeneration to test renal therapeutic agents of the invention (see, Vukicevic, et al. J. Bone Mineral Res. 2:533, 1987). A partial nephrectomy involves removing one kidney and ⅔ of the remaining kidney. After initial dramatic increases in plasma creatinine and BUN levels indicating an acute failure phase, the levels decline to an elevated level compared to normal levels. Approximately two weeks following surgery, the elevated level gradually increases with time as the animal progresses to chronic renal failure. Decapsulation is a mock surgery in which the kidneys are decapsulated but no renal tissue is removed or nephronic injury introduced. Decapsulated mice may be used as controls for kidney functionality comparison.

To determine if a renal therapeutic agent of the invention can prevent or delay the effects of acute renal failure, nephrectomized and decapsulated mice that have immediately recovered from their respective surgeries may be used. Mice may be divided into six groups as follows: 1) nephrectomized, receiving renal therapeutic agent; 2) nephrectomized, receiving vehicle buffer only; 3) nephrectomized, receiving no treatment; 4) decapsulated, receiving renal therapeutic agent; 5) decapsulated, receiving vehicle buffer only; and 6) decapsulated, receiving no treatment. Group one can be further divided into mice receiving 1, 3, 10, or 50 μg/kg body weight of renal therapeutic agent. Prior to or during the acute failure phase, nephrectomized mice may be administered their respective treatment by intraperitoneal injection twice daily for at least three days. Serum creatinine levels should be monitored prior to surgery, immediately following surgery, each day of treatment, and for each of at least four days following the last injection.

A decrease in serum creatinine levels in nephrectomized mice treated with a therapeutic agent of the invention may indicate a successful candidate for further testing of preventing nephronic degeneration or inducing nephronic regeneration. An increase in serum creatinine levels beyond increases of serum creatinine levels of vehicle-only treated mice may indicate a therapeutic agent capable of inducing nephronic degeneration. Such an agent may be useful in treating renal cell carcinoma or other kidney cancer type.

Example 3 Chronic Renal Failure Treatment

Chronic renal failure manifests itself progressively following an initial acute renal failure phase or renal insult without concomitant acute renal failure. Therapeutics of the present invention may be analyzed for use as a treatment for preventing or reversing chronic renal failure.

To determine if a therapeutic agent of the invention may prevent the development of chronic renal failure, nephrectomized and decapsulated mice that have recovered from their respective surgeries for at least two weeks may be used. Animals surviving the surgery for two weeks are past the acute renal failure phase and have not yet entered chronic renal failure.

Mice may be divided into six groups as follows: 1) nephrectomized, receiving renal therapeutic agent; 2) nephrectomized, receiving vehicle buffer only; 3) nephrectomized, receiving no treatment; 4) decapsulated, receiving renal therapeutic agent; 5) decapsulated, receiving vehicle buffer only; and 6) decapsulated, receiving no treatment. Group one can be further divided into mice receiving 1, 3, 10, or 50 μg/kg body weight of renal therapeutic agent. Mice may be treated intraperitoneally at least three times per week for a period of approximately 6-9 weeks. Serum creatinine levels should be monitored prior to treatment, during the treatment period, and at least 1 week following the treatment period.

During weeks 1-5 of treatment, nephrectomized mice may exhibit elevated serum creatinine levels compared to decapsulated mice. The amount of elevation between the groups of nephrectomized mice may correlate with the course of treatment used. If the serum creatinine levels are less elevated with increasing amounts of the renal therapeutic agent being tested, then the agent may be a successful candidate for further tests of preventing nephronic degeneration and inducing nephronic regeneration. If the serum creatinine levels become increasingly elevated with increasing amounts of the renal therapeutic agent in decapsulated mice, then the agent may be a nephronic degeneration inducing agent. Such an agent may be useful in treating renal cell carcinoma or other kidney cancer type.

Example 4 Renal Cell Carcinoma Treatment

Constitutive activation of the Wnt signaling pathway may be involved in the development of renal cell carcinoma and other kidney cancer types. The renal therapeutic agents of the invention that result in ectopic activation of the Wnt signaling pathway via interaction with the natural receptors of WISE and SOST may be useful in therapies treating renal cell carcinoma or other kidney cancer types. Therapeutics of the present invention may be analyzed for use as a treatment for preventing or reversing kidney cancer types.

To investigate novel therapeutic strategies for the treatment of human renal cell carcinoma, such as adoptive immunotherapy or cytokine therapy, murine renal cell carcinoma has been a particularly suitable animal model for assessing novel therapeutic approaches (Sayers, T. J., Wiltrout, T. A., McCormick, K., Husted, C., and Wiltrout, R. H., Cancer Res., 50: 5414-5420, 1990; Salup, R. R., and Wiltrout, R. H. Cancer Res., 46: 3358-3363, 1986). In this model, primary kidney tumors are induced by subcapsular renal injection of renal carcinoma (RENCA) cells with subsequent development of metastases in the lungs, lymph nodes, and spleen (Hillman, G. G., Droz, J., and Haas, G. H. In Vivo, 8: 77-80, 1994).

Murine RENCA cells originally obtained from a tumor that arose spontaneously in the kidney of BALB/c mice may be injected into BALB/c mice to generate a renal cell carcinoma model. Histologically, RENCA is a granular cell type adenocarcinoma, which is pleomorphic with large nuclei. Monolayers of murine RENCA cells may be grown in RPMI 1640 with phenol red supplemented with 10% FCS, 2 mM L-glutamine, 100 units penicillin/ml, and 100 μg of streptomycin/ml, RENCA cells may be cultured in a humidified atmosphere of 95% air and 5% carbon dioxide at 37° C.

Female BALB/c mice approximately 6-8 weeks of age (approximate weight, 20 g) may be injected with RENCA cells in 0.2-ml aliquots into the subcapsular space of the left kidney performed through a flank incision after the animals are anesthetized with 0.5-1.5 volume percent isoflurane, which may be used in combination with an oxygen flow of 1.5 l/min. The subcapsular renal injection of RENCA cells in a syngeneic BALB/c mouse may be followed by the progressive development of a primary tumor mass in the left kidney. One week after application, the primary tumor may be macroscopically visible; after 10 days, spontaneous metastases may develop in the regional lymph nodes, in the lung, the peritoneum, and the liver, allowing the RENCA model to be staged similarly to human renal cell carcinoma. The mean survival time of RENCA-bearing mice may be 32 days after RENCA cells are injected.

Treatments with a renal therapeutic agent of the invention or vehicle only may be initiated 1 day after tumor cell inoculation into the subcapsular space of the left kidney. Mice receiving the renal therapeutic agent may receive about 1, 3, 10, or 50 μg/kg body weight of the renal therapeutic agent intraperitoneally at least three times per week for a period of approximately 6-9 weeks. Serum creatinine levels should be monitored prior to treatment, during the treatment period, and at least 1 week following the treatment period. Animal weights should be taken every other day.

Two or 3 weeks after starting treatment, 6 or 10 mice, respectively, may be sacrificed in each group for determination of weight and volume of primary tumors, weight, and number of metastasis of the lung and metastasis formation in the abdominal lymph nodes. The volumes of primary tumors taken macroscopically may be calculated by taking and multiplying the distances of all three dimensions. The number of metastases in the lung and abdominal lymph nodes may be counted using a dissection microscope. In the abdominal cave, all visible lymph nodes may be counted for detection of metastasis, knowing that in healthy animals visible lymph nodes are usually absent. More animals may be sacrificed at later time points to monitor the progression or regression of tumor development.

A renal therapeutic agent of the invention that results in a significant decrease in primary tumor size or number of metastasis compared to mice treated with vehicle only may be successful candidates for renal cell carcinoma therapy. Agents that do not result in a significant decrease or result in a significant increase in primary tumor size or number of metastasis may be successful candidates for preventing nephronic degeneration or promoting nephronic regeneration.

Sequence Listing

The Sequence Listing, in computer readable form (CRF), is submitted on compact disc, and is hereby incorporated by reference into this patent application. A total of 217 sequences are being submitted. 

1. A method for treating nephronic degeneration comprising administering to a patient a composition comprising a therapeutically effective amount of an antibody that specifically binds a polypeptide selected from the group consisting of SEQ ID NOS: 35, 41, 52, 61, and 70, or a WISE polypeptide encoded by SEQ ID NO: 92, wherein the antibody interferes with the interaction between WISE and a WISE binding partner selected from the group consisting of LRP5, LRP6, and BMP.
 2. The method of claim 1, wherein a cause of the nephronic degeneration comprises chemical insult, physical insult, or disease that results in apoptosis or necrosis.
 3. The method of claim 1, wherein the antibody is a monoclonal antibody.
 4. The method of claim 1, wherein the antibody is a Fab or Fab₂ fragment.
 5. The method of claim 1, wherein the antibody specifically binds to WISE and the binding of the antibody to WISE prevents WISE interaction with LRP5 or LRP6 under conditions suitable for protein binding. 